Effect of the Clinical Usage of Tetracaine Hydrochloride Ophthalmic Solution on Multiple Antibiotic Resistant Staphylococcus Aureus

Abstract

Background: The emergence of resistant strain bacteria is rendering many antibiotics ineffective in the management of infectious diseases.

Objective: The purpose was to investigate the effect of Tetracaine hydrochloride usage on the emergence of a resistant strain of bacteria.

Materials and methods: A total of fifteen New Zealand White rabbits of either sex weighing between 1400-2700 grams were used for this study. Infectious agents of Ophthalmia neonatorum were cultured, isolated and identified. Their susceptibility to various antibiotics was assessed. A resistant strain was picked up and inoculated on the conjunctiva of the rabbits to induce bacterial conjunctivitis. Rabbits were divided into three groups of five rabbits each. Group A received Tetracaine as treatment, group B received 0.3% Ciprofloxacin as treatment and group C received normal saline as a treatment for 14 days. Outcome measures included bacterial colony count, clinical signs and post-antibiotic susceptibility test.

Results: The tetracaine significantly reduced clinical signs (P=0.012) compared to normal saline (control) and 0.3% Ciprofloxacin reduced clinical signs (P =0.003) compared to normal saline (control). This means there was a significant decrease in clinical scores with the interventions as compared to the normal saline which showed minimal change in clinical score. Tetracaine hydrochloride significantly reduced bacteria load (P≤0.0001). It decreased multiple antibiotic-resistant index by 20%.

Conclusion: Tetracaine has a supplemental antibiotic effect on resistant strain of bacteria and does not worsen antibiotic resistance of bacteria. Clinical usage of tetracaine ophthalmic solution should therefore be applied after conjunctival swaps or corneal scrapping have been taken.